Meeting the phosphorus consent with biological nutrient removal under UK winter conditions

Abstract

It is estimated that up to 342 wastewater treatment plants (Wwtps) in England and Wales will require a phosphorus (P) consent by 2010. Although biological P removal is considered to be the most sustainable option for P removal, it has always been problematic for plants that remove both nitrogen and P due to the inadequate concentration of organic material during wet periods. Two biological nutrient removal (BNR) configurations, the Johannesburg (JHB) process and a combined JHB and five-stage Bardenpho process, were evaluated over a period of 2 years to assess the impact of sewage strength on bio-P removal. The JHB achieved an average effluent total phosphorus (TP) of 2.4 mg/L and the combined JHB and five-stage process averaged 1.4 mg/L effluent TP. The major problems affecting the performance of both configurations were: dissolved oxygen (DO) in the recycled mixed liquor, nitrate in the return activated sludge (RAS) and low influent biological oxygen demand (BOD) concentrations. Acetate dosing proved successful as a source of volatile fatty acids (VFAs) in the anaerobic zone during periods of low-strength sewage. An acetate dosing strategy based on the influent flow rate to the plant was found to be a simple and effective technique that ensured that a consent of o1 mg TP/L could be met.

Understanding the growth of the bio-struvite productionBrevibacterium antiquumin sludge liquors

“…All these bacteria which have been successfully applied is commercially viable biological process for the treatment of wastewater and sludge dewatering liquors [27,28]. This was accomplished through application of processes and reactors with particular engineered operational conditions that work as a selective pressure limiting other competing microorganisms and allow for them to proliferate in open mixed-culture conditions [11,22].…”

“…Both acetate and oleic acid showed a significant and comparable impact on the growth rate of B. antiquum with acetate having a better response (µ = 1.92 1/d) than oleic acid (µ = 1.77 1/d). The addition of a carbon source in WWTPs, is a common practice in denitrification and enhanced biological phosphate removal processes, in order to stimulate the proliferation of selected bacteria such as denitrifiers and phosphorus accumulating organisms[22,23]. A similar approach might also benefit the growth of B. antiquum.…”

Assessing the effectiveness of pollutant removal by macrophytes in a floating wetland for wastewater treatment

“…They represent a means of potentially improving the treatment performance of the conventional pond systems by integrating the beneficial aspects of emergent macrophytes without being constrained by the requirements of shallow water depth (Dalu et al 2012;Wanda et al 2015). Similarly, they also offer some advantages over the conventional sedimentrooted wetlands such as their ability to cope up with variable water depths that are typical of any event-driven storm water system (Kerr-Upal et al 2000;Manyumba et al 2009;Srivastava et al 2014Srivastava et al , 2016.…”

Traditional or Conveyor belt marking: Exploring the way forward at Great Zimbabwe University, Zimbabwe

“…This has eliminated remarking of scripts. The National Examination Council of Rwanda, indicated that in the past traditional marking in which each script was marked by one Marker led to hasty and sloppy marking as the Markers were paid according to the number of scripts they would have marked [Rwanda Focus, 2009].The Kenyan National Examination Council introduced the conveyor belt and to ensure marking reliability the Markers were trained and sat for the examination they were going to mark in order to judge their content level [Manyumba and Mutwiri, 2009].Conveyor belt marking in Tanzania, among other reasons was adopted to reduce the time for marking, queries and biases by Markers [East African Community Meeting of Secondary Education Examination Report, 2010].…”